Abstract
Influence of α-receptor blockade on the time-dependent change in the effect of furosemide (a loop diuretic agent) was examined. Furosemide (30 mg/kg) was given orally to the doxazosin (an α1-blocker)- or vehicle-treated rats at 12 AM or 12 PM. Urine volume and urinary excretions of sodium and furosemide for 8 hr were significantly greater at 12 AM than at 12 PM in the vehicle-treated animals. However, such time-dependent changes in these parameters disappeared in the doxazosin-treated rats. These results suggest that the α1-receptor-mediated stimuli are involved in the mechanism of the time-dependent change in the effect of furosemide.
